Pathology

Aetiology

traumatic: closed head trauma with an anterior base of skull fracture is most common cause for CSF rhinorrhoea 2, natural barriers between anterior cranial fossa and paranasal sinuses can be disrupted leading to rhinorrhoea based on the severity of trauma

Radiographic features

CT

large osseous defects can be visualised on plain CT

CT cisternography is the diagnostic modality for diagnosing an occult site of CSF leak. It is performed after injecting contrast into the thecal sac; however, this procedure highly depends on the patient's position and timing

MRI

3D high-resolution T2W and T1W sequences are useful in diagnosing this condition

coronal reformations can depict the osseous defects with a greater degree of accuracy

Radionuclide studies

have higher sensitivity in diagnosing leaks but have poor anatomic resolution

History and etymology

Leakage of spinal fluid into either the nose or the ear was first described as a pathologic entity in 1899 by Sir St Clair Thomson 3.